Erik wrote: "One secret, which an ASC guy told me once, but I agree with, is listen to the music in the hallway. You can go up and down the hall and quickly pick out the well tuned rooms without ever having to walk in."
From outside the open doorway, with NO line-of-sight to the speakers, ALL you can hear is the reverberant sound. And if that reverberant sound is spectrally correct (and the dynamics are preserved), there’s an excellent chance the sound in the room is likewise quite good.
This reverberant sound is dominated by the speaker’s off-axis response, and is of course modified by the room, but it would take some very capable targeted room treatment to "fix" a speaker which has inherently poor off-axis response.
On the other hand, an unamplified voice or acoustic instrument would sound totally convincing from outside the room assuming the room isn’t absolutely dreadful, imo in large part because the off-axis energy of the unamplified voice or instrument is inherently correct.
So while I understand what your ASC guy is saying, listening from outside the room can tell you a great deal about the speakers even if there are no acoustic treatments in play. Among other things, a spectrally correct reverberant field is conducive to long-term fatigue-free listening, assuming the direct sound is also correct.
I don’t have anything against using room treatment, but if your speakers start out with spectrally-correct off-axis energy, then your room treatment can be focused on enhancing something which is already pretty good, instead of needing to focus on fixing something which isn’t. (Examples on request.)
Erik again: "Honestly, I simply don’t know how audiophiles audition most equipment in a hotel room, at all."
I understand your skepticism which is why I had hoped we could cross paths at an audio show.
If the speaker system effectively takes the room out of the equation, then the room is no longer superimposing its signature atop every piece of music you play. This would be a situation where you could audition equipment in a hotel room.
Duke